Cellular communication networks may incorporate wireless terminal devices and base stations for the purpose of providing communications services such as telephony, data, video, messaging, chat, and broadcast. Multiple wireless terminals may be connected to a serving cell that is controlled by a base station (BS). Typical access schemes employed in cellular networks include frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), orthogonal frequency division multiple access (OFDMA), and single-carrier frequency division multiple access (SC-FDMA). A BS may also be referred to as a NodeB in Universal Mobile Telecommunications System (UMTS), an evolved NodeB (eNB) in Long-Term Evolution (LTE) specified by the 3rd Generation Partnership Project (3GPP), a base transceiver system (BTS), or an access point (AP).
In general, an eNB may be fixed hardware (i.e., not mobile), but in some cases, such as when deployed in a car, may also be mobile. The wireless terminal devices may be portable hardware. The wireless terminal device may be referred to as a user equipment (UE), a mobile station, a cellular phone, a personal digital assistant (PDA), or a wireless modem card. Uplink (UL) communication may refer to communication from a UE to a eNB, while downlink (DL) communication may refer to communication from the eNB to the UE. An eNB may comprise radio frequency (RF) transmitters and receivers used to directly communicate with UEs, which may either be in a fixed location or freely move around the eNB. Similarly, each UE may comprise RF transmitters and receivers used to communicate directly with the eNB.
Conventional cellular communication networks operate in a point-to-point, single-cell transmission fashion where a UE is uniquely connected to and served by a single eNB at a given time. An example of such a network is described in 3GPP Long-Term Evolution (LTE) Release 8 (Rel-8), which is incorporated by reference. Advanced cellular systems are intended to further improve the data rate and performance by adopting multi-point-to-point or coordinated multi-point (CoMP) communication where multiple base stations can cooperatively design downlink transmissions to simultaneously serve a UE. An example of such a system is the 3GPP LTE-Advanced (LTE-A) system. Those approaches greatly improve received UE signal strength by transmitting the same signal to the UE from different eNBs. This is particularly beneficial for cell edge UEs that observe strong interference from neighboring base stations.